Hot runner system

Abstract

The present invention discloses a hot runner system, which includes a driving cylinder, a valve pin driven by the driving cylinder to reciprocate up and down, and a manifold plate having a glue inlet and a runner. The valve pin is partially located in the runner. Wherein, the hot runner system further includes a valve pin sleeve surrounding the outer periphery of the valve pin and a fixing block. The valve pin sleeve is provided with a needle sleeve inner hole for the valve pin to pass through and adapted to the valve pin. The fixing block is provided with a fixing block inner hole for the valve pin to pass through and adapted to the valve pin. The fixing block is embedded in the manifold plate. The valve pin sleeve is at least partially embedded in the fixing block, and the valve pin sleeve does not contact the manifold plate. This hot runner system avoids the expansion of the needle sleeve inner hole caused by the heat of the manifold plate, and greatly reduces the risk of plastic overflow due to the increase in the fitting clearance between the valve pin and the valve pin sleeve.

Description

Technical Field

[0001] The present invention relates to the field of hot runner molds, and particularly to a hot runner system. Background Art

[0002] Currently, the injection molds commonly used in the injection molding industry are hot runner injection molds. Compared with ordinary molds, plastic products injection-molded through a hot runner system have higher quality, and the hot runner system has the advantages of saving raw materials, improving production efficiency, and having a high degree of automation.

[0003] A hot runner system generally includes a driving cylinder, a valve pin driven by the driving cylinder to reciprocate up and down, and a manifold plate. The manifold plate has a resin inlet and a runner communicated with the resin inlet. The valve pin is partially located in the runner. A valve pin sleeve is arranged on the outer periphery of the valve pin, and all or most of the valve pin sleeve is buried in the manifold plate. It is characterized in that, in order to smoothly inject the plastic material into the cavity, the material must be in a liquid state. To keep the material in a liquid state, the manifold plate needs to be heated. During the heating process of the manifold plate, the heat of the manifold plate will be directly transferred to the valve pin sleeve, and the inner hole of the valve pin sleeve will expand due to the influence of heat. When the expansion amount of the inner hole of the valve pin sleeve is greater than the reasonable clearance between the valve pin and the valve pin sleeve, at this time, when the manifold plate is filled with plastic under pressure, the plastic in the runner of the manifold plate will overflow outside the manifold plate through the clearance between the valve pin and the valve pin sleeve. Summary of the Invention

[0004] The purpose of the present invention is to provide a hot runner system, which avoids the expansion of the inner hole of the needle sleeve caused by the heat of the manifold plate, and greatly reduces the risk of plastic overflow caused by the increase in the clearance between the valve pin and the valve pin sleeve.

[0005] To achieve one of the above-mentioned invention purposes, an embodiment of the present invention provides a hot runner system, which includes a driving cylinder, a valve pin driven by the driving cylinder to reciprocate up and down, and a manifold plate having a resin inlet and a runner. The valve pin is partially located in the runner, and is characterized in that

[0006] the hot runner system further includes a valve pin sleeve surrounding the outer periphery of the valve pin and a fixing block. The valve pin sleeve is provided with a needle inner hole for the valve pin to pass through and adapted to the valve pin. The fixing block is provided with a fixing block inner hole for the valve pin to pass through and adapted to the valve pin. The fixing block is embedded in the manifold plate. At least part of the valve pin sleeve is embedded in the fixing block, and the valve pin sleeve does not contact the manifold plate.

[0007] As a further improvement of an embodiment of the present invention, the valve pin extends along a longitudinal axis, and a plane passing through the longitudinal axis is defined as a longitudinal plane. The projection of the valve pin sleeve on the longitudinal plane is far from the projection of the manifold plate on the longitudinal plane.

[0008] As a further improvement of an embodiment of the present invention, the valve needle extends along the longitudinal axis, and in the extension direction of the longitudinal axis, the valve needle sleeve partially protrudes from the fixing block.

[0009] As a further improvement of an embodiment of the present invention, the fixing block includes a connecting portion threadedly connected to the diverter plate and a stopping portion connected to the connecting portion and located outside the diverter plate.

[0010] As a further improvement of one embodiment of the present invention, the valve needle extends along the longitudinal axis, and the hot runner system also includes a valve needle sleeve pressure cap connected to the fixed block. In the horizontal direction perpendicular to the longitudinal axis, the valve needle sleeve pressure cap is located between the fixed block and the valve needle sleeve, and the valve needle sleeve pressure cap presses the valve needle sleeve to the fixed block.

[0011] As a further improvement of an embodiment of the present invention, the valve needle sleeve pressing cap is threadedly connected to the fixing block.

[0012] As a further improvement of an embodiment of the present invention, the hot runner system further includes an upper mold plate and a height adjustment pad, the valve needle extends along the longitudinal axis, and in the extension direction of the longitudinal axis, the height adjustment pad is located between the upper mold plate and the diverter plate.

[0013] As a further improvement of an embodiment of the present invention, in the extension direction of the longitudinal axis, the height adjustment pad is located between the upper template and the fixed block.

[0014] As a further improvement of an embodiment of the present invention, the height adjustment pad is fixedly connected to the upper template by bolts.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: since a fixed block is provided, the fixed block is embedded in the manifold, and then the valve needle sleeve is at least partially embedded in the fixed block, the valve needle sleeve is prevented from contacting the manifold, so that during the heating process of the manifold, the heat will not be directly transferred to the valve needle sleeve, but the heat will be first transferred to the fixed block, and then indirectly transferred to the valve needle sleeve through the fixed block, which greatly reduces the heat transfer efficiency. In addition, since the valve needle sleeve is located outside the manifold, it is more conducive to the cooling of the valve needle sleeve itself. Therefore, the expansion of the inner hole of the needle sleeve caused by the heat of the manifold is avoided, and the risk of plastic overflow caused by the increase of the matching gap between the valve needle and the valve needle sleeve is greatly reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a schematic diagram of a hot runner system in a specific embodiment of the present invention;

[0017] Figure 2 yes Figure 1 A partial enlarged schematic diagram in the middle. DETAILED DESCRIPTION

[0018] The specific embodiments shown in the accompanying drawings will be described in detail for the present invention below. However, these embodiments do not limit the present invention, and any structural, method, or functional transformation made by those of ordinary skill in the art based on these embodiments is included within the protection scope of the present invention.

[0019] In each of the diagrams of the present application, for the convenience of illustration, certain dimensions of the structure or part are exaggerated relative to other structures or parts. Therefore, it is only used to illustrate the basic structure of the subject matter of the present application.

[0020] Spatial relative position terms used herein, such as "upper", "above", "lower", "below", etc., are for the purpose of facilitating description of the relationship of one unit or feature relative to another unit or feature as shown in the accompanying drawings. The spatial relative position terms are intended to include different orientations of the device in use or operation other than the orientation shown in the figures. For example, if the device in the figure is flipped, the unit described as being "below" or "beneath" other units or features will be "above" other units or features. Therefore, the exemplary term "below" can encompass both the upper and lower orientations. The device can be oriented in other ways (rotated 90 degrees or other orientations), and the spatially related descriptive terms used herein can be interpreted accordingly.

[0021] As Figure 1 and Figure 2 shown, a specific embodiment of the present invention provides a hot runner system. The hot runner system includes a driving cylinder 10, a valve pin 12 driven by the driving cylinder 10 to reciprocate up and down, and a manifold plate 15 having a glue inlet 14 and a runner 16. The valve pin 12 is partially located in the runner 16. The hot runner system further includes a nozzle 17 provided below the manifold plate 15. A nozzle runner 19 and a glue outlet (not shown) communicating with the nozzle runner 19 are provided in the nozzle 17. The valve pin 12 extends into the nozzle runner 19 and can reciprocate up and down in the nozzle runner 19 to open or close the glue outlet.

[0022] The hot runner system further includes a valve pin sleeve 18 surrounding the outer periphery of the valve pin 12 and a fixing block 20. The valve pin sleeve 18 is provided with a needle sleeve inner hole for the valve pin 12 to pass through and adapted to the valve pin 12. The fixing block 20 is provided with a fixing block inner hole for the valve pin 12 to pass through and adapted to the valve pin 12. The fixing block 20 is embedded in the manifold plate 15. The valve pin sleeve 18 is at least partially embedded in the fixing block 20, and the valve pin sleeve 18 does not contact the manifold plate 15.

[0023] In this preferred embodiment, since the fixing block 20 is provided, the fixing block 20 is embedded in the flow dividing plate 15, and then at least a part of the valve needle sleeve 18 is embedded in the fixing block 20, so as to prevent the valve needle sleeve 18 from contacting the flow dividing plate 15. Therefore, during the heating process of the flow dividing plate 15, heat will not be directly transferred to the valve needle sleeve 18. Instead, heat will first be transferred to the fixing block 20 and then indirectly transferred to the valve needle sleeve 18 through the fixing block 20, greatly reducing the heat transfer efficiency. Thus, it is avoided that the inner hole of the needle sleeve expands due to the heat of the flow dividing plate 15, and the risk of plastic overflow caused by the increase in the fitting clearance between the valve needle 12 and the valve needle sleeve 18 is greatly reduced.

[0024] The valve needle 12 extends along the longitudinal axis 22. A plane passing through the longitudinal axis 22 is defined as the longitudinal plane. The projection of the valve needle sleeve 18 on the longitudinal plane is away from the projection of the flow dividing plate 15 on the longitudinal plane. That is to say, preferably, the projection of the valve needle sleeve 18 on the longitudinal plane does not overlap with the projection of the flow dividing plate 15 on the longitudinal plane. With this setting, the valve needle sleeve 18 is kept as far away from the flow dividing plate 15 as possible, which is more conducive to the self-cooling of the valve needle sleeve 18. Of course, the projection of the valve needle sleeve 18 on the longitudinal plane and the projection of the flow dividing plate 15 on the longitudinal plane can also be set to partially overlap, as long as there is no direct contact between the valve needle sleeve 18 and the flow dividing plate 15.

[0025] Furthermore, the valve needle 12 extends along the longitudinal axis 22. In the extending direction of the longitudinal axis 22, a part of the valve needle sleeve 18 protrudes from the fixing block 20.

[0026] The fixing block 20 includes a connecting portion 24 threadedly connected to the flow dividing plate 15 and a stop portion 26 connected to the connecting portion 24 and located outside the flow dividing plate 15. Preferably, the outer diameter of the stop portion 26 is larger than the outer diameter of the connecting portion 24. Of course, the outer diameter of the stop portion 26 can also be set to be smaller than or equal to the outer diameter of the connecting portion 24.

[0027] The fixing block 20 further includes an upper end portion 28 connected to the stop portion 26. The upper end portion 28 and the connecting portion 24 are located on both sides of the stop portion 26. Preferably, the outer diameter of the upper end portion 28 is larger than the outer diameter of the connecting portion 24, and the outer diameter of the upper end portion 28 is smaller than the outer diameter of the stop portion 26. Of course, the outer diameter of the upper end portion can also be set to be smaller than or equal to the outer diameter of the connecting portion 24, and the outer diameter of the upper end portion 28 can also be set to be larger than or equal to the outer diameter of the stop portion 26.

[0028] The hot runner system further includes a valve needle sleeve compression cap 29 connected to the fixed block 20. In the horizontal direction perpendicular to the longitudinal axis 22, the valve needle sleeve compression cap 29 is located between the fixed block 20 and the valve needle sleeve 18, and the valve needle sleeve compression cap 29 presses the valve needle sleeve 18 against the fixed block 20. Further, the outer diameter of the connecting portion 24 is larger than the outer diameter of the valve needle sleeve compression cap 29. Preferably, twice the outer diameter of the valve needle sleeve compression cap 29 is still smaller than the outer diameter of the connecting portion 24. With such a setting, the distance between the valve needle sleeve 18 and the manifold plate 15 is larger, the valve needle sleeve 18 is further away from the manifold plate 15, and the heat transferred from the manifold plate 15 to the valve needle sleeve 18 is smaller.

[0029] In addition, in the vertical direction parallel to the longitudinal axis 22, preferably, the sum of the lengths L1 of the upper end portion 28 and the stop portion 26 is greater than the length L2 of the connecting portion 24. Preferably, the lower part of the valve needle sleeve 18 is higher than the lower side surface of the stop portion 26. With such a setting, the distance between the valve needle sleeve 18 and the manifold plate 15 in the vertical direction is as large as possible, the valve needle sleeve 18 is as far away from the manifold plate 15 as possible, and the heat transferred from the manifold plate 15 to the valve needle sleeve 18 is as small as possible. Of course, the lower part of the valve needle sleeve 18 can also be set to be at the same height as the lower side surface of the stop portion 26. Here, the lower side surface of the stop portion 26 is the bottom surface of the stop portion 26 facing the manifold plate 15. The lower part of the valve needle sleeve 18 is perpendicular to the longitudinal axis 22, and the lower part of the valve needle sleeve 18 abuts against the fixed block 20.

[0030] In this preferred embodiment, the valve needle sleeve compression cap 29 is threadedly connected to the fixed block 20. The valve needle sleeve 18 has a protruding portion 30 protruding outward in the direction perpendicular to the longitudinal axis 22, and the valve needle sleeve compression cap 29 presses the protruding portion 30, thereby pressing the valve needle sleeve 18 against the fixed block 20. The fixed block 20 has a receiving groove for receiving the valve needle sleeve 18 and the valve needle sleeve compression cap 29.

[0031] The hot runner system further includes an upper template 32 and a height adjustment spacer 34. In the extending direction of the longitudinal axis 22, the height adjustment spacer 34 is located between the upper template 32 and the manifold plate 15. The drive cylinder 10 is disposed on the upper template 32. The height adjustment spacer 34 has a hollow portion 36, and the portions of the valve needle sleeve 18 and the valve needle sleeve compression cap 29 protruding from the fixed block 20 are located in the hollow portion 36.

[0032] Further, the height adjustment spacer 34 is located between the upper template 32 and the fixed block 20. The height adjustment spacer 34 is fixedly connected to the upper template 32 by bolts 38. The lower end of the height adjustment spacer 34 abuts against the fixed block 20.

[0033] It should be understood that although this specification is described in terms of embodiments, not every embodiment contains only one independent technical solution. This narrative style of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0034] The series of detailed descriptions listed above are only specific descriptions of the feasible embodiments of the present invention, and they are not intended to limit the protection scope of the present invention. Any equivalent embodiments or changes made without departing from the technical spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A hot runner system, the hot runner system comprising a drive cylinder, a valve pin driven by the drive cylinder to reciprocate up and down, and a manifold plate having a resin inlet and a runner, the valve pin being partially located in the runner, characterized in that, the hot runner system further comprises a valve pin sleeve surrounding the outer periphery of the valve pin and a fixing block, the valve pin sleeve being provided with a needle sleeve inner hole for the valve pin to pass through and adapted to the valve pin, the fixing block being provided with a fixing block inner hole for the valve pin to pass through and adapted to the valve pin, the fixing block being embedded in the manifold plate, at least a part of the valve pin sleeve being embedded in the fixing block, and the valve pin sleeve not contacting the manifold plate; the fixing block comprises a connecting portion threadedly connected to the manifold plate and a stop portion connected to the connecting portion and located outside the manifold plate; the valve pin extends along a longitudinal axis, the hot runner system further comprises a valve pin sleeve pressing cap connected to the fixing block, in a horizontal direction perpendicular to the longitudinal axis, the valve pin sleeve pressing cap being located between the fixing block and the valve pin sleeve, and the valve pin sleeve pressing cap pressing the valve pin sleeve against the fixing block.

2. The hot runner system according to claim 1, wherein the valve pin extends along a longitudinal axis, a plane passing through the longitudinal axis is defined as a longitudinal plane, and a projection of the valve pin sleeve on the longitudinal plane is away from a projection of the manifold plate on the longitudinal plane.

3. The hot runner system according to claim 1, characterized in that, the valve pin extends along a longitudinal axis, in the extending direction of the longitudinal axis, a part of the valve pin sleeve protrudes from the fixing block.

4. The hot runner system according to claim 1, wherein, the valve pin sleeve pressing cap is threadedly connected to the fixing block.

5. The hot runner system according to claim 1, characterized in that, the hot runner system further comprises an upper template and a height adjusting spacer block, the valve pin extends along a longitudinal axis, in the extending direction of the longitudinal axis, the height adjusting spacer block is located between the upper template and the manifold plate.

6. The hot runner system according to claim 5, characterized in that, in the extending direction of the longitudinal axis, the height adjusting spacer block is located between the upper template and the fixing block.

7. The hot runner system according to claim 6, wherein the height adjusting spacer block is fixedly connected to the upper template by bolts.

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